About this replacement
Google Pixel 9 Pro / Pixel 9a — 3.9V Li-Polymer Replacement Battery (G526Q)
This 3.9V, 4950mAh Li-Polymer cell replaces part number G526Q in the Google Pixel 9 Pro (G3Y12, GTF7P, GXQ96) and Pixel 9a. It fits devices where the original cell has degraded, lost charge capacity, or failed to hold voltage under screen and modem load. Rated at 19.31Wh, it matches the OEM energy spec for these models.
- G3Y12, GTF7P, GXQ96, Pixel 9a fit group: These four models share the same G526Q connector pinout, BMS handshake protocol, and 3.9V nominal voltage rail — which is why one cell covers all four. The fuel gauge IC in each reads the same cell chemistry signature on the first boot cycle.
- Bench tested on actual hardware: We ran the cell through a full charge-discharge cycle on a Pixel 9 Pro unit. The BMS accepted the cell without error flags, the charge IC stepped through trickle, CC, and CV phases correctly, and the coulomb counter initialised on the first complete cycle.
- First-cycle fast charge protocol: On first use after installation, disable fast charging for one complete discharge-charge cycle. This allows the fuel gauge IC to map the new cell's discharge curve before high-current USB-PD charging pushes elevated current into an uncalibrated cell, reducing the risk of early percentage drift.
Sudden shutdown at 20–30% on the replacement cell
This is a voltage cliff problem, not a capacity problem. Under peak modem load — 5G radio, GPS, and screen active simultaneously — the cell voltage drops faster than the fuel gauge IC predicts, and the phone shuts down before the reported percentage reaches zero. It happens most often on a fresh cell because the coulomb counter is still calibrated to the old cell's impedance curve. Run two full discharge-charge cycles without fast charging, and the IC recalibrates to the new cell. After that, shutdowns below 20% drop significantly. If the issue persists after three cycles, check that the battery connector is fully seated — a partial connection raises contact resistance and accelerates voltage sag.
USB-PD fast charge not negotiating on the first cycle after swap
After a cell replacement, the Pixel's charge IC sometimes stays in standard 5V/0.9A mode and refuses to step up to USB-PD fast charge rates. This happens because the charge controller applies a conservative profile until it completes one full charge cycle on the new cell and confirms BMS communication is stable. Reboot the device after the first full charge completes. If fast charging still does not activate, clear the cached charging data by powering off, removing the USB cable, waiting 30 seconds, then reconnecting — this resets the charge IC negotiation state.